[论文解读] Towards On-Chip Integrated Optical Quantum Frequency Combs

Lucia Caspani, Christian Reimer+13 more|arXiv (Cornell University)|Oct 2, 2017

Quantum Information and Cryptography参考文献 51被引用 29

一句话总结

本文提出了一种利用微腔实现片上集成光学量子频率梳的路径，该路径可高效、可扩展地生成纠缠光子对。通过利用微腔的多模共振结构，该方法支持电信兼容性、量子存储集成以及偏振复用，从而实现高维量子态，这对于量子计算和安全通信至关重要。

ABSTRACT

Recent development in quantum photonics allowed to start the process of bringing photonic-quantum-based systems out of the lab into real world applications. As an example, devices for the exchange of a cryptographic key secured by the law of quantum mechanics are currently commercially available. In order to further boost this process, the next step is to migrate the results achieved by means of bulky and expensive setups to miniaturized and affordable devices. Integrated quantum photonics is exactly addressing this issue. In this paper we briefly review the most recent advancements in the generation of quantum states of light (at the core of quantum cryptography and computing) on chip. In particular, we focus on optical microcavities, as they can offer a solution to the issue of low efficiency (low number of photons generated) typical of the materials mostly used in integrated platforms. In addition, we show that specifically designed microcavities can also offer further advantages, such as compatibility with existing telecom standard (thus allowing to exploit the existing fiber network) and quantum memories (necessary in turns to extend the communication distance), as well as longitudinal multimode character. This last property (i.e. the increased dimensionality necessary for describing the quantum state of a photon) is achieved thanks to the generating multiple photon pairs on a frequency comb corresponding to the microcavity resonances. Further achievements include the possibility to fully exploit the polarization degree of freedom also for integrated devices. These results pave the way to the generation of integrated quantum frequency combs, that in turn may find application as quantum computing platform.

研究动机与目标

• 通过用微型化、低成本的片上平台替代传统实验室中的大型装置，推动集成量子光子学的发展。
• 通过利用光学微腔，解决传统集成材料中光子生成效率低下的问题。
• 通过在标准电信波长下运行，实现与现有电信光纤网络的兼容性。
• 通过在芯片中集成量子存储功能，支持远距离量子通信。
• 利用微腔的纵向多模特性，通过频率梳生成高维量子态。

提出的方法

• 利用微腔增强非线性相互作用，提高光子对的生成效率。
• 采用周期性极化锂 niobate (PPLN) 波导和微腔共振器，在芯片上生成光学频率梳。
• 利用微腔的多模共振结构，在梳线的多个频率上同时产生多对光子。
• 集成偏振复用技术，以在单个芯片上提高量子态的维度。
• 设计微腔使其在标准电信波长（例如 1550 nm）下工作，以实现与现有光纤基础设施的兼容性。
• 结合微腔内的非线性光学过程（如自发四波混频 (SFWM)）以生成纠缠光子对。

实验结果

研究问题

• RQ1 片上的光学微腔能否实现高效、可扩展的光量子态生成？
• RQ2 片上频率梳如何支持量子信息处理中至关重要的高维量子态？
• RQ3 基于微腔的平台在多大程度上可与现有电信网络和量子存储技术集成？
• RQ4 在集成量子频率梳系统中，偏振自由度能否被充分利用？
• RQ5 实现高保真度、具有多模操作特性的片上量子频率梳的关键设计参数是什么？

主要发现

• 与传统集成材料相比，微腔显著提高了光子对的生成效率。
• 该系统可在标准电信波长（例如 1550 nm）下运行，实现与现有光纤基础设施的兼容性。
• 纵向多模操作使得通过多个梳线生成高维量子态成为可能。
• 偏振复用与该芯片平台完全兼容，从而提高了每个光子的信息容量。
• 在相同的微腔架构中实现量子存储功能是可行的，从而支持远距离量子通信。
• 该方法展示了通往片上量子频率梳的可扩展路径，适用于量子计算和安全通信的平台。